[FFmpeg-devel] [PATCH 3/3] avformat/options: Only allocate AVCodecContext for demuxers
Andreas Rheinhardt
andreas.rheinhardt at outlook.com
Sat Feb 3 13:29:57 EET 2024
The muxer's AVCodecContext is currently used for exactly one thing:
To store a time base in it that has been derived via heuristics
in avformat_transfer_internal_stream_timing_info(); said time base
can then be read back via av_stream_get_codec_timebase().
But one does not need a whole AVCodecContext for that, a simple
AVRational is enough.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
If it were not for lavd, I would add a ff_demux_add_stream()
to be used internally for demuxers instead of avformat_new_stream().
libavformat/avformat.c | 59 +++++++++++++++++++++++-------------------
libavformat/dump.c | 14 +++++-----
libavformat/internal.h | 2 ++
libavformat/options.c | 8 +++---
4 files changed, 47 insertions(+), 36 deletions(-)
diff --git a/libavformat/avformat.c b/libavformat/avformat.c
index 41b1c4e7d9..9cacaef87d 100644
--- a/libavformat/avformat.c
+++ b/libavformat/avformat.c
@@ -729,8 +729,6 @@ AVRational av_guess_frame_rate(AVFormatContext *format, AVStream *st, AVFrame *f
{
AVRational fr = st->r_frame_rate;
const AVCodecDescriptor *desc = cffstream(st)->codec_desc;
- AVCodecContext *const avctx = ffstream(st)->avctx;
- AVRational codec_fr = avctx->framerate;
AVRational avg_fr = st->avg_frame_rate;
if (avg_fr.num > 0 && avg_fr.den > 0 && fr.num > 0 && fr.den > 0 &&
@@ -739,6 +737,9 @@ AVRational av_guess_frame_rate(AVFormatContext *format, AVStream *st, AVFrame *f
}
if (desc && (desc->props & AV_CODEC_PROP_FIELDS)) {
+ const AVCodecContext *const avctx = ffstream(st)->avctx;
+ AVRational codec_fr = avctx->framerate;
+
if ( codec_fr.num > 0 && codec_fr.den > 0 &&
(fr.num == 0 || av_q2d(codec_fr) < av_q2d(fr)*0.7 && fabs(1.0 - av_q2d(av_div_q(avg_fr, fr))) > 0.1))
fr = codec_fr;
@@ -753,13 +754,19 @@ int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
{
const AVCodecDescriptor *desc = cffstream(ist)->codec_desc;
const AVCodecContext *const dec_ctx = cffstream(ist)->avctx;
- AVCodecContext *const enc_ctx = ffstream(ost)->avctx;
AVRational mul = (AVRational){ desc && (desc->props & AV_CODEC_PROP_FIELDS) ? 2 : 1, 1 };
- AVRational dec_ctx_tb = dec_ctx->framerate.num ? av_inv_q(av_mul_q(dec_ctx->framerate, mul))
+ AVRational dec_ctx_framerate = dec_ctx ? dec_ctx->framerate : (AVRational){ 0, 0 };
+ AVRational dec_ctx_tb = dec_ctx_framerate.num ? av_inv_q(av_mul_q(dec_ctx_framerate, mul))
: (ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO ? (AVRational){0, 1}
: ist->time_base);
- enc_ctx->time_base = ist->time_base;
+ AVRational enc_tb = ist->time_base;
+#if FF_API_TICKS_PER_FRAME
+FF_DISABLE_DEPRECATION_WARNINGS
+ int ticks_per_frame = dec_ctx ? dec_ctx->ticks_per_frame : 1;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+
/*
* Avi is a special case here because it supports variable fps but
* having the fps and timebase differe significantly adds quite some
@@ -773,35 +780,31 @@ int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
&& 0.5/av_q2d(ist->r_frame_rate) > av_q2d(dec_ctx_tb)
&& av_q2d(ist->time_base) < 1.0/500 && av_q2d(dec_ctx_tb) < 1.0/500
|| copy_tb == AVFMT_TBCF_R_FRAMERATE) {
- enc_ctx->time_base.num = ist->r_frame_rate.den;
- enc_ctx->time_base.den = 2*ist->r_frame_rate.num;
+ enc_tb.num = ist->r_frame_rate.den;
+ enc_tb.den = 2*ist->r_frame_rate.num;
} else
#endif
- if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx->framerate.num &&
- av_q2d(av_inv_q(dec_ctx->framerate)) > 2*av_q2d(ist->time_base)
+ if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx_framerate.num &&
+ av_q2d(av_inv_q(dec_ctx_framerate)) > 2*av_q2d(ist->time_base)
&& av_q2d(ist->time_base) < 1.0/500
|| (copy_tb == AVFMT_TBCF_DECODER &&
- (dec_ctx->framerate.num || ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO))) {
- enc_ctx->time_base = dec_ctx_tb;
- enc_ctx->time_base.den *= 2;
+ (dec_ctx_framerate.num || ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO))) {
+ enc_tb = dec_ctx_tb;
+ enc_tb.den *= 2;
#if FF_API_TICKS_PER_FRAME
-FF_DISABLE_DEPRECATION_WARNINGS
- enc_ctx->time_base.num *= dec_ctx->ticks_per_frame;
-FF_ENABLE_DEPRECATION_WARNINGS
+ enc_tb.num *= ticks_per_frame;
#endif
}
} else if (!(ofmt->flags & AVFMT_VARIABLE_FPS)
&& !av_match_name(ofmt->name, "mov,mp4,3gp,3g2,psp,ipod,ismv,f4v")) {
- if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx->framerate.num
- && av_q2d(av_inv_q(dec_ctx->framerate)) > av_q2d(ist->time_base)
+ if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx_framerate.num
+ && av_q2d(av_inv_q(dec_ctx_framerate)) > av_q2d(ist->time_base)
&& av_q2d(ist->time_base) < 1.0/500
|| (copy_tb == AVFMT_TBCF_DECODER &&
- (dec_ctx->framerate.num || ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO))) {
- enc_ctx->time_base = dec_ctx_tb;
+ (dec_ctx_framerate.num || ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO))) {
+ enc_tb = dec_ctx_tb;
#if FF_API_TICKS_PER_FRAME
-FF_DISABLE_DEPRECATION_WARNINGS
- enc_ctx->time_base.num *= dec_ctx->ticks_per_frame;
-FF_ENABLE_DEPRECATION_WARNINGS
+ enc_tb.num *= ticks_per_frame;
#endif
}
}
@@ -810,18 +813,19 @@ FF_ENABLE_DEPRECATION_WARNINGS
&& dec_ctx_tb.num < dec_ctx_tb.den
&& dec_ctx_tb.num > 0
&& 121LL*dec_ctx_tb.num > dec_ctx_tb.den) {
- enc_ctx->time_base = dec_ctx_tb;
+ enc_tb = dec_ctx_tb;
}
- av_reduce(&enc_ctx->time_base.num, &enc_ctx->time_base.den,
- enc_ctx->time_base.num, enc_ctx->time_base.den, INT_MAX);
+ av_reduce(&ffstream(ost)->transferred_mux_tb.num,
+ &ffstream(ost)->transferred_mux_tb.den,
+ enc_tb.num, enc_tb.den, INT_MAX);
return 0;
}
AVRational av_stream_get_codec_timebase(const AVStream *st)
{
- return cffstream(st)->avctx->time_base;
+ return cffstream(st)->avctx ? cffstream(st)->avctx->time_base : cffstream(st)->transferred_mux_tb;
}
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
@@ -846,7 +850,8 @@ void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
return;
}
st->time_base = new_tb;
- sti->avctx->pkt_timebase = new_tb;
+ if (sti->avctx)
+ sti->avctx->pkt_timebase = new_tb;
st->pts_wrap_bits = pts_wrap_bits;
}
diff --git a/libavformat/dump.c b/libavformat/dump.c
index aff51b43f6..01e2306479 100644
--- a/libavformat/dump.c
+++ b/libavformat/dump.c
@@ -550,12 +550,14 @@ static void dump_stream_format(const AVFormatContext *ic, int i,
}
// Fields which are missing from AVCodecParameters need to be taken from the AVCodecContext
- avctx->properties = sti->avctx->properties;
- avctx->codec = sti->avctx->codec;
- avctx->qmin = sti->avctx->qmin;
- avctx->qmax = sti->avctx->qmax;
- avctx->coded_width = sti->avctx->coded_width;
- avctx->coded_height = sti->avctx->coded_height;
+ if (sti->avctx) {
+ avctx->properties = sti->avctx->properties;
+ avctx->codec = sti->avctx->codec;
+ avctx->qmin = sti->avctx->qmin;
+ avctx->qmax = sti->avctx->qmax;
+ avctx->coded_width = sti->avctx->coded_width;
+ avctx->coded_height = sti->avctx->coded_height;
+ }
if (separator)
av_opt_set(avctx, "dump_separator", separator, 0);
diff --git a/libavformat/internal.h b/libavformat/internal.h
index f93832b3c4..520f1a5229 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -416,6 +416,8 @@ typedef struct FFStream {
int64_t cur_dts;
const struct AVCodecDescriptor *codec_desc;
+
+ AVRational transferred_mux_tb;
} FFStream;
static av_always_inline FFStream *ffstream(AVStream *st)
diff --git a/libavformat/options.c b/libavformat/options.c
index 75ec86ce05..03e6a2a7ff 100644
--- a/libavformat/options.c
+++ b/libavformat/options.c
@@ -283,11 +283,12 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
goto fail;
sti->fmtctx = s;
- sti->avctx = avcodec_alloc_context3(NULL);
- if (!sti->avctx)
- goto fail;
if (s->iformat) {
+ sti->avctx = avcodec_alloc_context3(NULL);
+ if (!sti->avctx)
+ goto fail;
+
sti->info = av_mallocz(sizeof(*sti->info));
if (!sti->info)
goto fail;
@@ -323,6 +324,7 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
sti->pts_buffer[i] = AV_NOPTS_VALUE;
st->sample_aspect_ratio = (AVRational) { 0, 1 };
+ sti->transferred_mux_tb = (AVRational) { 0, 1 };;
#if FF_API_AVSTREAM_SIDE_DATA
sti->inject_global_side_data = si->inject_global_side_data;
--
2.34.1
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